对镇原地区上三叠统延长组长8油层组沉积相进行研究,在大量掌握研究区区域地质资料和消化吸收前人研究成果的基础上,以沉积学的基本原理和方法为指导,并配合钻井资料、测井分析等资料,结合邻区地层、沉积相研究成果。研究认为镇原地区上三叠统延长组长8油层发育有三角洲相和湖泊相两种沉积相,以辫状河三角洲前缘为主。三角洲前缘水下分流河道骨架砂体是最主要的油气储集体。 Based on the research on the sedimentary facies of Chang 8 reservoir of Yanchang Formation of Upper Triassic in Zhenyuan area and based on a large quantity of the regional geological data and the digestion and absorption of previous research results, the basic principles and methods of sedimentology are taken as the guide. With drilling data, logging analysis and other data, combined with the adjacent area strata, sedimentary facies research results. The study shows that there are two sedimentary facies of delta-phase facies and lacustrine facies in Chang-8 reservoir of Yanchang Formation of Upper Triassic in Zhenyuan area, with the front of braided delta being dominant. Delta front submarine distributary channel sand body is the most important oil and gas reservoir.